Angle-resolved photoelectron spectroscopy of N2O measured as a function of photon energy from 14 to 70 eV

Abstract

Angle-resolved photoelectron spectra have been taken of the first four bands of N2O, using photons from synchrotron radiation. From these data, the partial cross section and the angular distribution parameter β have been obtained over a range of photon energies from 14 to 70 eV for the first four valence orbitals: 2π, 7σ, 1π, and 6σ. Calculations, based on the multiple scattering Xα method, also have been performed to obtain the partial cross sections and β values for comparison with experiment. An important element in the understanding of these data is the presence of shape resonances particularly in the photoionization of the 7σ and 6σ orbitals. Although the calculations are not in good quantitative agreement with experiment, they are able qualitatively to give a correct account of the overall behavior. In the case of the photoelectron spectra of the 7σ and 6σ orbitals, the vibrationally resolved bands were studied independently, particularly for their β values. Evidence of autoionization was found from detailed study of data on the 7σ orbital. In addition, marked changes in β over the vibrational envelope have been noted and possible explanations are advanced based on the effects of shape resonances and vibronic coupling.